1. Field of the Invention
The present invention relates to the cleaning of the inside surfaces of pipelines used in the transportation of gaseous media, and more specifically to a device that decreases the cleaning time and improves the quality of the cleaning process.
2. Summary of the Prior Art
Currently, there are several procedures and devices for removing impurities from inside and on internal surfaces of pipelines used for transportation of gaseous media. The impurities may include, for example, pipeline system construction residuals such as welding electrodes, various metal objects, etc. In addition, some impurities, such as condensates and impurities from compressor stations arise as a consequence of the abrasive processes as the transported medium contacts the pipeline interior surface.
Devices used for pipeline cleaning are principally made as sliding mechanisms in the pipeline with the utilization of physical properties of the transported media affecting the corresponding mechanisms. They contain a carrying body where the cleaning elements are fixed. The structure and material of the elements corresponds to the cleaning method.
Among the most frequently used are collar type cleaning devices where collars are the crucial cleaning elements, and their circumferential surface fits snuggly within the internal surface of the pipeline. They are suitable for cleaning of pipelines from fluid impurities.
Cleaning devices including two cleaning elements, namely, a collar and a magnetic segment, are more common than the collar-only devices previously described. In these devices, the space between the exterior surface of the collar and the interior surface of the pipeline, which is approximately 100 up to 200 mm, partially restricts the cleaning efficiency of the device. The structure of these magnetic devices determines their ability to remove from the pipeline, in addition to fluid impurities, also metallic components of impurities. As a consequence of the fact prior art devices do not rotate during the cleaning, and are not equipped to break the bond between impurities and the pipeline surface, especially in the case of higher adherence of impurities to the internal wall of the pipeline, these prior art devices have low cleaning efficiency.
Cleaning devices equipped with collars and brushes with metal bristles are comparatively widespread. The utilization of brushes in the cleaning process on one side has favourable influence on the cleaning quality of the internal surface of the pipeline and, in fact, the equipment is able to clean the pipeline from all impurities but, consequently, this increases the load on the collar part of the equipment and therefore has negative influence on its wear.
Prior cleaning devices where the cleaning is accomplished with collars equipped with metal tips at the contact area with the pipeline wall are utilized mainly for the removal of thin impurities as, for example, wax from crude oil pipelines. In this case, it is a special cleaning device and this is accompanied by higher financial costs for its manufacture. Equally as in the case of the previous device, at higher levels of clogging of the pipeline, the collars are excessively loaded and therefore quickly worn down.
Recently, cleaning devices have been produced which, in addition to the previously mentioned cleaning elements, are equipped with a speed regulator for controlling the sliding motion of the cleaning device through the pipeline. The aim of this design is to optimize the speed of the device depending, for example, on the extent of the clogging or on the flow of the transporting medium to thereby achieve higher cleaning quality.
U.S. Pat. No. 4,027,349 discloses a cleaning device consisting of a body means adapted to be received in a pipe, relative means supported by said body means adapted for coaxial rotation in the pipe. A plurality of brushes circularly spaced around the outer periphery of the relative means are mounted for rotation about an axis directed toward the wall of the pipe. A gas motor means rotates each brush about the axis. The relative means has a flow passage means for delivering gas from a non-relative source carried by the body means to the gas motor means to operate the gas motor means. The axis of each brush is disposed at a small forward angle from a direction radial of the rotative means and with respect to the direction of rotation of the rotative means, whereby the leading edge of each brush applies less pressure against the pipe wall than the trailing edge of the brush, thereby reducing brush wear. The cleaning device also includes a means for biasing each brush against the pipe wall.
Pipeline cleaning devices may consist of one, two, and sometimes three parts connected by hinges. The two- and three-part hinged cleaning devices are suitable, above all, for negotiating smaller diameter pipelines. Simple cleaning devices are used for larger dimensioned pipelines. A common disadvantage of existing pipeline cleaning devices is that their cleaning motion is limited to sliding through the interior of the pipeline.
From among such tools we note the cleaning device described in European Patent No. EP 0 076 434 A1 which discloses a cleaning device having at least one working head fixable in a working position and being movable along defined feed paths through the interior of the pipelines or vessels which are not visible from the outside. Instruments mounted on the at least one working head include rotatable brushes mounted on the working head which apply pressure against the inner wall surfaces to be cleaned. At least one suction nozzle is mounted on the working head and is movable into alignment with a given brush engagement region of a pipeline or vessel. The cleaning device further comprises an injector having a suction side connected to the nozzle, a discharge side and a propulsion nozzle, a propellant line feeding the propulsion nozzle of the injector from outside the pipeline or vessel, and a dust collecting bag connected downstream of the discharge side of the injector.
The shortcomings described above are addressed by the present inventive cleaning device. The device includes cleaning elements that rotate about the longitudinal axis of the device and slide along the interior of the pipeline in a spiraling motion as the device proceeds through the pipeline. The device and the cleaning elements are propelled by the transported medium. The device comprises a carrying body with a shield at the front end of the carrying body. A transfer port at the back end of the carrying body leads to a speed regulator mounted on the shield for controlling the speed of the device. On the carrying body, particularly, on outside circumference walls, there are fixed individual parts of the device which can be removed and replaced. From these parts there are at least two carry and guide parts, at least one sealing and scraping part, one brush, a main magnet, and the revolving mechanism and guiding part. Each sealing and scraping part, carry and guide part, and brush part have circular cross-sectional profile. The outside circumference of the magnet follows the internal circumference of the pipeline, and between these two circumferences there is a gap. Each sealing and scraping part, carry and guide part, are made of flexible material, such as polyurethane and brush have a circular cross-sectional profile. The outside circumference of the magnet is less than the internal circumference of the pipeline, creating a gap. The sealing and scraping part and carrying and guiding parts are made of flexible material, such as a suitable polyurethane material. The placement of carrying and guiding parts stabilizes the device""s motion with regard to its center of gravity. The parts are arranged in the following order from the shield of the device: carrying and guiding part, sealing and scraping part, brush, main magnet, revolving mechanism and the guide, and carrying and guiding part or the set of parts.
According to the invention, the cleaning mechanism will provide, as a practical matter, the removal of all kinds of impurities appearing in pipelines, either of metal origin, as for example impurities arising from the abrasive wearing, impurities which remained in the pipeline systems after their construction, especially welding electrodes and their residual parts, iron scales, or other impurities as, for example, condensates. The structure and mutual arrangement of individual parts of the device are based on the device""s requirement to simultaneously slide and rotate to accomplish the cleaning function of the device. Regulation of the forward speed of the device, in combination with the revolution of the device around its longitudinal axis, will properly clean the internal space of the pipeline from metal particles while evenly distributing the caught particles around the outside circumference of the device.
Additionally, the cleaning motion of the present inventive cleaning device enables it to achieve a high standard of cleaning on the first pass through a pipeline system. Repeated cleanings with the device act as a check cleaning or a final cleaning depending on the level of clogging of the pipeline. The present inventive cleaning device achieves at least comparable quality pipeline system cleaning as the prior art devices,and in less time.